I agree with your assessment of transcripts in your blog posthttp://webaim.org/blog/wcag2-last-call/. Transcripts provide universal
access to multimedia content. They work for deaf/blind individual, may
provide better support for some people with cognitive disabilities, and
have the added benefit of working without the need for specialized
players, audio support within a player or bandwidth requirements. A
transcript created with well structured html will also be indexed better
by search engines, and will provide good navigational support within
browsers and screen readers. Finally, creating a good transcript is the
first step in preparing good captions and audio descriptions.

If I had my way, transcripts would be level A and captions and audio
description would be level AA. Captions and audio description certainly
add value but they do not necessarily provide essential access to the
broadest range of individuals.

WCAG 2.0 has been moved to Last Call status. You are invited to review
the draft guidelines at http://www.w3.org/TR/WCAG20/ and make comments
by February 1, 2008.

I've taken only a brief look at the document and reviewed some previous
criticisms I had. Most have been addressed. Additional commentary is
available on our blog at http://webaim.org/blog/wcag2-last-call/